1. Field of the Invention
The present invention relates to reproducing audio/video (AV) data, and, more particularly, to an information storage medium containing interactive graphics streams capable of changing the reproducing state of AV data, and a reproducing method and apparatus that use the interactive graphics streams capable of changing the reproducing state of AV data.
2. Description of the Related Art
FIG. 1 is a diagram showing a variety of streams being multiplexed into a main stream.
Referring to FIG. 1, a main stream 110 of multimedia pictures is formed by multiplexing a video stream 102, an audio stream 104, a presentation graphics stream 106 to provide subtitles, and an interactive graphics stream 108 to provide a menu containing buttons for interaction with a user. The interactive graphics stream 108 includes a plurality of segments.
FIG. 2 is a diagram showing the structure of a display set included in the interactive graphics stream 108.
Referring to FIG. 2, the interactive graphics stream 108 is formed with a plurality of display sets, each of which includes a plurality of segments. Each of the segments forming the display set will now be explained. An interactive composition segment (ICS) 210 defines display information of an “interactive display” in the interactive graphics stream 108. The “interactive display” is used to provide graphics elements such as a button corresponding to a command. A palette definition segment (PDS) 220 is used to define a palette which provides output colors or degrees of transparency that should be applied to pixel values in a graphics plane in relation to the interactive graphics stream 108. There can be a plurality of object definition segments (ODS) 230-1 through 230-n, which are actual graphics data in the interactive graphics stream 108. An end segment 240 is used to indicate the end of a display set.
This interactive graphics stream 108 is reproduced together with an AV stream. When a menu is displayed on the screen, in order to navigate the menu while the AV stream is being reproduced, the reproduction of AV data continues even during reproduction of the interactive graphics stream corresponding to the menu. Accordingly, some scenes of a movie may be missed during menu navigation, or if the menu box takes up a large part of the screen, important scenes may be missed.